Operating mechanism for circuit breakers



July 18, 1950 J. D. FINDLEY, JR., ErAL 2,515,994

` OPERATING MECHANISM Foa CIRCUIT BREAmRs Filed Deo. 13, 1946 2 Sheets-Sheet l Figi D f 4r Y Lfh l Y". l I I -J Z9 .93vr 4l Y l 43 l 0l .57 .55 el 59 [7 /17 5a 73 H5 2:5 67`\ D 7/ /27 IIA l ,65- l L?? [/55 /45 V if 69 I| hl, [43 /4/ X5@ ,5, dan .,)s 3 lv, "9 83 /57 97 95 :7 -..1* A fr Li 5( I 185 I i 2o www ATTORNEY July 18 1950 v J. DIFINDLEY, JR., Erm. 2,515,994

OPERATING MECHANISM FOR CIRCUIT BREAKERS Filed Deo. 13. 1946 2 Sheets-Sheet 2 ATTORNEY Patented July 18, 1950 UNITED STATES PATENT OFFICE.

OPERATING MECHANISM FOR CIRCUIT BREAKERS Application December 13, 1946, Serial No. 716,104

8 Claims.

This invention relates to circuit breakers and more particularly to operating mechanisms for circuit breakers,

An object of the invention is to provide a circuit breaker with an improved high-speed operating mechanism wherein the breaker contact means are trip-free of the closing means.

Another object of the invention is to provide a circuit breaker with an improved operating mechanism having a few parts, the elements of which are arranged in compact form to improve the eiiiciency of operation.

Another object of the invention is to provide a circuit breaker with an improved operating mechanism which is simple in construction, reliable and efficient in operation and inexpensive to manufacture.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will best be understood from the following detailed description of one embodiment thereof when read in commotion with the accompanying drawings, in which:

Fig. 1 is a side elevational view, partly in section, of a circuit breaker embodying the principles of the invention;

Fig. 2 is a detailed sectional view taken through the operating mechanism showing the mechanism in the closed circuit position.

Fig. 3 is a sectional view similar to Fig, 2 but showing the operating mechanism in the tripped position just before the mechanism is reset;

Fig. 4 is a sectional view taken through the operating mechanism showing the mechanism in the automatically reset position; and

Fig. 5 is an enlarged detail view of the latching mechanism.

Referring to Fig. 1 of the drawings, the circuit breaker is of the roll-out type and is mounted on a truck comprising a pair of side plates (only one being shown) which are rigidly joined by cross members I3, |5, ll and I9 to form a rigid framework for supporting the circuit breaker. 'The truck is mounted on wheels 28 to facilitate rolling the circuit breaker into and out of a cubicle in order to connect and disconnect the breaker in an electrical circuit.

The circuit breaker is of the multi-pole type (only one pole being shown) and comprises a plurality of pairs of separable contact means (only one pair being shown) indicated senerally at 2|, a common operating mechanism indicated at 23, a trip device 25 and a closing means 21.

The contact means comprises stationary contacts 23 and 3| mounted respectively on terminal members 33 and 35 which are, in turn, rigidly supported on a back plate 31. The back plate 31 is rigidly supported by angular brackets 33 (only one being shown) rigidly secured to the side plates of the truck. A switch arm 4| pivotally mounted at 43 on the terminal member 35 carries a bridging contact member 45 for cooperating with the stationary contacts 29 and 3| to open and close the circuit. The switch arm also carries a movable arcing contact 41 which cooperates with a stationary arcing contact 49 mounted on the terminal 33 for drawing an arc upon opening movement of the switch arm 4|,

The switch arm 4| for each pole of the breaker is operatively connected by means of an insulating operating rod 5| to the operating mechanism 23. The upper end of the rod 5| is pivotally connected by means of a pivot pin 53 to the switch arm 4| and the lower end of the rod 5| is connected by means of a screw 55 and a. lock nut 51 to an angular cross bar 59 common to all of the poles of the breaker. The cross bar 59 is pivotally connected by means of pivot pins 52 at its ends to ar: operating levercomprising a pair of spaced levers 5| )Fi`g. 1) and 63 (Figs. 2, 3 and 4). The operating levers 6| and 63 are rigidly connected by an integral U-shaped cross member and are pivotally supported on a shaft 61. The shaft E1, in turn, is mounted in the side members of a generally U-shaped frame 69 (Fig. 1) supported on the cross members |3, I5 and I1, the right hand end of the frame 59 being secured to a bracket 1| which is secured by means of bolts 'I3 to the cross member l1.

In addition to the operating lever 63, the operating mechanism comprises a closing lever 15 (Figs. 2, 3 and 4) also pivotally mounted on the shaft 61. The closing lever 15 comprises a pair of spaced levers (only one being shown) rigidly connected by an integral cross bar 11. The closing lever 15 is connected by means of a pivot pin 18 to one end of a link 8| a pair of spaced links which has its other end connected by means of a pin 83 to the movable armature 85 of the closing solenoid 21 (Fig, 1) The operating lever 63 and the closing lever 15 are operatively connected by means of a thrust transmitting toggle comprising toggle links 81 and 88 pivotally connected together by means of a knee pivot pin 3|. The toggle link l1 is pivotally connected to the operating lever by means of a pivot pin 93 and the toggle link 83 which comprises a pair of spaced parallel links is pivotally connected by means of the pivot pin 19 to the closing lever 15. 'Ihe closinglever15 is held in closed position (Fig. 2) by means of a latch 95 pivotally mounted on a rod 91 supported in the side members of the frame 69 (Fig. 1). The latch 95 is biased by means of a spring 99 to latching position wherein a shoulder formed by a recess therein engages a roller mounted on the pin 19.

The toggle 81-89 is normally held in a slightly underset position by means of a. latch member |03 pivotally mounted on the shaft 61 and connected to the knee of the toggle by means of a pair of links (only one being shown). The links |05, disposed one on each side of the latch member |03, have one end pivotally connected by means of a pivot pin |01 to the latch member |03 and the other end connected to the knee pin 9| of the toggle 81-89. The latch member |03 is normally releasably restrained in latching position by means of the latching and tripping mechanism 25 which is more clearly shown in Fig. 5.

The latching and tripping mechanism comprises a U-shaped trip member |09 pivoted on a pivot pin mounted in the side members (only one being shown) of a U-shaped bracket ||3. The bracket 3 is rigidly secured to a bracket ||5 which, in turn is rigidly secured to the side members of the frame 69. The bracket ||5 is also secured to the cross members I3 (Fig. 1) by means of` spacers 1. The trip member |09 carries a latch roller ||9 pivoted on a pin |2| in. the side member of the trip member, which roller is biased by means of a spring |23 into engagement with a shoulder |25 on the latch member |03 to restrain this member and the toggle 81-89 in the closed or thrust transmitting position.

The trip member |09 is so constructed that it will not, of itself, restrain the latch member |03 against releasing operation. For. thisreason a trigger latch comprising a channel-shaped latch member |21 is provided. The latch member |21 is pivotally supported on a pin |29 mounted in the U-shaped bracket ||3 and is provided with a latching projection |3| which normally engages a latching projectionA |33 on the trip member `|09 to restrain the roller 9 inlatchin'g engagement with the shoulder |25 on the latch member |03. The latch member 21 is biased by means of a spring |35 to latching position and is adapted to be operated eithermanually or automatically to unlatching position to eiect release of the operating mechanism and opening of the circuit breaker by means of a tripping electromagnet indicated generally at |31 (Figs. 1 and 2).

The tripping electromagnet comprises a yoke member |39 (Fig. 1) secured to a plate |4| rigidly mounted on the left-hand end of the U- and latched position. In the closed position, the operating lever 6|-63 (Figs. 1 and 2) is biased in a clockwise or opening direction by means of a coil spring |59 disposed in a cylinder |6| (Fig. 1) rigidly mounted on the frame 69. A piston |63 disposed forl reciprocal movement in the cylinder is connected by means of a link |65 to the arm 6| of the operating lever and the spring |59 is compressed between lthe piston |63 and a plate |61 secured to the upper end of the cylinder. The cylinder |6| and the piston |63 also serve as a dash pot to absorb the shock of the final opening movement of the operating mechanism. The spring |59 acting through the piston |03 and the link |65 biases the operating lever 9 |63 in a clockwise direction. The biasing force of the spring |59 is transmitted by means of the underset toggle 91-69 to the closing lever 15 which is normally restrained in the position shown in Fig. 2 by the latch 95. The force of the spring |59,therefore, tends to cause the toggle 81-89 to collapse toward the right (Fig. 2) which is prevented by the link |05 and the latching mechanism. A component of the force tending to collapse the toggle 81-89 is applied through the link |05 to the latch member |03 tending to rotate this member in a counterclockwise direction. The latch member |03 is restrained from tripping rotation by the slip-off the circuit controlled by the breaker, the trip-v shaped frame 69. In addition to the yoke member |39, the tripping electromagnet includes an energizing coil |43,v a movable armature (not shown) and a trip rod |45 attached to the movable armature.

The closing solenoid 21 (Fig. l), in addition to the movable armature 65, also comprises a fixed core member |41 and an energizing coil |49. The closing; solenoid 21 is supported between the frame 69 (Fig. 1) and an end plate |5| which is secured to the frame 69 by means of bolts |53 and spacers |55.

Referring particularly to Fig. 2 of the drawings,

the operating mechanism is shown in the closed type latch ||9|25 and this latch, in turn, is

restrained by the latch |3||33 (Fig. 5).

Upon the occurrence of an abnormal condition, such for instance as an overload current in ping electromagnet |31 (Figs. 1 and 2) is en ergized by well known means such, for instance, as a fault relay. When the tripping electromagnet is energized, the movable armature (not shown) thrusts the trip rod |45 upwardly to engage and operate the trip member |21 in a clockwise or tripping direction. Clockwise movement of the latch member |21 disengages the latch projection |3| from the latch projection |33 to.

unlatch the trip member |09. When this occurs, the force tending to collapse the toggle 81-89, a component of which is applied to the latch member |03, forces the roller latch' ||9 out of the path of counterclockwise movement of the shoulder |25 whereupon the latch member |03 is free to rotate in tripping direction and no longer maintains the toggle 81-89 in its underset position. Upon release of the latch member |03, thetoggle 81-89 immediately collapses under the' influence of the spring 59 which immediately rotates the operating lever 6|-63 to the position in which it appears in Fig. 3 to effect openingof circuit breaker contacts.

The toggle 81-89 is reset to its underset posi tion and the latch member |03 is reset and relatched during the opening operation. The resetting of the toggle 81-89 and relatching of the latch member |03 is eiected by means of a pair of springs |69 (only one being shown) tensioned between a bracket |1| secured to the armature 85 of the closing solenoid and projections |13 on lthe closing lever 15. During the collapse of the the link 8| to the left rotating the lever 15 clockwise until it strikes a stop stud |8|. Clockwise rotation of the lever 15 straightens the toggle ,81-88 and moves the armature 85 to the left to its unattracted position. vStraightening of the toggle 81-89 thrusts the link |05 to the left thereby rotating the latch member |03 clockwise to its latching position at which time the trip member |08 is moved by the spring |23 to reengage the roller ||8 with the shoulder |25 and the spring |35 reengages the latch |3| with the latch |33. The parts are shown in the reset and relatched position in Fig. 4.

After the mechanism is reset and relatched following an automatic opening operation, the contacts are closed by energization of the closing solenoid 21. The solenoid 21 may be energized from any suitable source either automatically or by means of a manually operated switch means. When energized, the solenoid 21 attracts its armature 85 and through the link 8| rotates the closing lever 15 in a counterclockwise direction about the shaft. Since, at this time, the latch member |03 is restrained in latched position, the toggle 81-89 is held by the link |05 in thrust transmitting position. The counterclockwise or closing movement of the closing lever 15 is, therefore, transmitted through the toggle 81-88 to the operating' lever IBI-63 to rotate the operating lever counterclockwise to its closed position to operate the switch arms 4| for all of the poles of the breaker to closed position. As the operating mechanism arrives at its closed position, the latch, L95, urged by the spring 99, reengages the latch roller I| to restrain the operating mechanism and the contact means in the closed position. The final closing movement of the operating mechanism is retarded by the spring |59 which is compressed during the latter portion of the closing operation, the operating mechanism being nally arrested in the fully the Figure 3 position, but, upon deenergization of the closing solenoid, the springs |69 will immediately reset the parts to the Figure 4 position causing the latch member |03 to be relatched preparatory to a subsequent closing operation.

From the foregoing description it will be apparent that there is provided an extremely compact circuit breaker operating mechanism comprising relatively few parts and wherein all of the main elements of the operating mechanism are mounted on a common shaft.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from the essential features of the invention.

We claim as our invention:

1. In a circuit breaker comprising relatively movable contact means, operating means for said contact means comprising an operating lever operable to effect opening of said contact means, a closing lever for operating said operating lever to close said contact means, thrust transmitting means connecting said levers, releasable means normally restraining said thrust transmitting means in thrust transmitting position, a single l pivot upon which said operating lever, said closclosed position by the movable armature 85 of the closing solenoid striking the stationary core |41. The toggle compressing the operating lever lil-83 and the rods 5| is prevented from going over center to the left of a line drawn through the pivots 53-61 by means of a projection |83 on the operating lever engaging the bracket ||5.

The contact means of thebreaker are tripfree of the closing means. That is, if, when the circuit breaker is operated to the closed position, the overload current condition has been cleared the breaker will remain in the closed contact position. However, should the overload current still persist the tripping electromagnet |31 will be energized upon closure of the contacts and operate the trip mechanism 25 in the previously described manner to effect immediate release of the latch member |03 and collapse of the toggle 81-88. This permits the breaker mechanism, including the switch arms 4| for all of the poles of the breaker, to go to the open position even though the closing solenoid 21 remains energized, or irrespective of the position of the closing lever 15. During such a trip-free operation, the collapse of the toggle 81-89 causes the roller |15 to engage and move the latch 95 to unlatching position. If, at this time, the closing solenoid 21 is still energized the mechanism will be held in ing lever and said releasable means are concentrically pivoted, and trip means operable in response to overload currents to release said releasable means to thereby cause collapse of said thrust transmitting means and opening of said contact means.

2. In a circuit breaker comprising relatively movable contact means, operating means for said contact means comprising an operating lever operable to eiect opening of said Contact means, a closing lever operable to close said contact means, a single shaft pivotally supporting both of said levers, a thrust transmitting toggle operatively relating said levers, a releasable member also pivotally mounted on said shaft but independently of said levers, means operatively relating said toggle and said releasable member to normally maintain said toggle in thrust transmitting position, and trip means operable to release said releasable means to thereby permit collapse of said toggle and opening of said contact means.

3. In a circuit breaker comprising relatively movable contact means, operating means for said contact means comprising an operating lever operatively related to said contact means and operable to eiect opening of said contact means, a closing lever for actuating said operating lever to close said contact means, a shaft pivotally supporting said levers, latch means releasably restraining said closing lever in closed position, a thrust transmitting toggle operatively relating said levers, a releasable member pivoted on said shaft for restraining said toggle in thrust transmitting position, trip means operable to release said releasable member to permit collapse of said toggle and -opening of said contact means, and means operable upon collapse of said toggle to cause said latch means to release said closing lever to thereby reset said toggle to thrust transmitting position.

4. In a circuit breaker comprising relatively movable contact means, operating mechanism for said contact means comprising an operating lever operable to effect opening of said contact means, a closing lever for operating said operating lever to close said contact means, thrust transmitting s 7 means operatively relating said levers, a releasable member normally restraining said thrust transmitting means in thrust transmitting position, a single shaft upon which both of said levers and said releasable member are` concentrically pivoted, trip means operable to release of said releasable means to thereby effect collapse of said thrust transmitting means and opening oi' said contact means, means operable by said thrust transmitting means upon collapse thereof for effecting resetting of said thrust transmitting means to thrust transmitting position, and power means for operating said levers to close said conber, releasable means pivoted on said common pivot means for normally restraining said thrust transmitting means in thrust transmitting position, and trip means operable to release said releasable means to-cause said thrust ytransmitting means to permit opening movement of said operating member and said contact means.

6. In a circuit breaker comprising relatively movable contact means, power operating means for actuating saidcontactmeans to closed position comprising a closing lever, power means for actuating said closing lever, anv operating lever operatively related to said contact means, a pivot common to both of said levers for pivotally supporting said lever for independent movement, a thrust transmitting toggle operatively relating said closing lever and said operating lever for transmitting the movement of said closing lever to said operating lever to close said contact means,-

latch means pivoted on said common pivot re- .leasably restraining said toggle in thrust transmitting position, and trip means operable to eifect release of said toggle and opening of said contacts irrespective of the position of said closing lever.

7. In a circuit breaker-comprising relatively movable contact means, operating mechanism for said contact means comprising a pivoted member operatively related tosaid contact means and operable to effect opening of said contactmeans,

a pivoted closing member, a pivot common to both oi' said members for pivotally supporting 'said'- members, power means for actuating said closing member, a lthrust transmitting toggle operatively relating said operating member and said closing member for normally restraining said operating member in closed position, and means pivoted on said common pivot independently of said members for causing said toggle to permit opening movement of 'said operating member irrespective of the position of said closing member.

8. In a circuit breaker comprising a movable switch member biased to open circuit position, operating mechanism therefor comprising an operating lever movable about a, fixed pivot and operatively related to said movable switch member, a closing lever movable about said flxed pivot, an operating toggle operatively relating said levers, a first holding means also movable about said xed pivot for releasably holdingsaid operating toggle in an underset position to hold said movable switch member in closed position, a second holding means for holding said closing lever in closed positions, trip means operable in response to overload currents for causing said nrs-t holding means to release said operating toggle to REFERENCES CITED The following references are of record in le of this patent: l

UNITED l STATES PATENTS Number Name Date 1,190,060 Wolff July 4, 1916 1,950,162 CaSby -./)Malt 6, 1934 1,957,273 Langfritz May 1, 1934 FOREIGN PATENTS Number Country Date Germany Nov. 29, 1917 

